1. Field of the Invention
The present invention relates to a reciprocation type electric shaver, and especially relates to a configuration of an outside blade unit.
2. Description of the Related Art
Conventionally, an outside blade unit of a reciprocation type electric shaver, for example, shown in WO94/23913 or Japanese Lid-Open Patent Publication No. 9-253353 comprises an outside blade unit configured by a main blade, a slit blade and an outside blade holder to which these blades are installed capable of freely floating up and down.
In the above conventional electric shaver, it is configured that a hooking piece formed to protrude from each end of the slit blade in longitudinal direction thereof engages with an hooking groove formed on each end wall of the outside blade holder in the longitudinal direction so that the hooking piece can be moved freely up and down.
Since the hooking piece, however, is engaged with the hooking groove only in the longitudinal direction, the slit blade may be disengaged from the outside blade holder due to shortage of hooking dimension of the hooking piece in the longitudinal direction when the slit blade is floated with inclination so that an end of the slit blade goes down lower than the other end.
Alternatively, for preventing the disengagement of the hooking piece of the slit blade from hooking groove of the outside blade holder, it is necessary to reduce a displacement of the slit blade in floating motion. In such a case, since the displacement of the slit blade in floating motion is reduced, following characteristic to concave and convex surface of skin becomes worse, so that contact feeling to the skin becomes worse, consequently.
Furthermore, even if the hooking dimension of the hooking piece in the longitudinal direction is enlarged so as not to prevent the disengagement of the hooking piece in the floating with inclination, it is necessary to make a depth of the hooking groove deeper. Consequently, the end walls of the outside blade holder in the longitudinal direction become thicker, so that the outside blade holder becomes larger. Furthermore, an area of a surface of the outside blade holder that contacts human skin may be increased, so that the contact feeling to skin becomes much worse.